This invention relates to the field of fluid motors having fluid impellers for generating either thrust or rotational power. More particularly the invention relates to fluid motors in which one or more fluid motors provide the propulsive mechanism for one or more other fluid motors, so as to provide an amplified output.
Patent application Ser. No. 09/682,455 was filed Sep. 5, 2001 and issued as U.S. Pat. No. 6,457,671 on Oct. 1, 2002 in the name of the present applicant for a funneled rotary foil (FRF), which patent is incorporated herein by reference. The funneled rotary foil in the aforementioned patent application added a funnel strip to the blade of a rotating airfoil to scoop in and increase the velocity of air flowing over the suction side of the air foil, and added fins to the blade tips to block radial flow from the blade tips.
More specifically, the invention of Ser. No. 09/682,455 claimed a funneled rotary foil comprising a rotatably mounted hub having an axis of rotation, a plurality of circumferentially spaced blades mounted on the hub so as to extend in a generally radial direction from the hub to a blade tip so as to be rotatable in a plane of rotation about the axis, each blade having a cross-section defining an airfoil with a suction side, a leading edge, a trailing edge, and defining a chord extending therebetween, the airfoil increasing gradually in thickness from the leading edge to a point of maximum thickness and thereafter decreasing in thickness, a fin attached to the blade tip and adapted to block radial flow from the blade tip, and a funnel strip mounted on each of the blades uniformly spaced from the suction side thereof and extending in a generally radial direction along the full length of the blade, the funnel strip having an inlet edge defining a funnel inlet area with the airfoil leading edge and having an outlet edge spaced from the suction side at approximately the point of maximum thickness to define a funnel outlet area, the funnel plate being oriented with respect to the chord so as to scoop in and increase the velocity of air flowing over the suction side of the airfoil, and dimensioned such that the ratio of inlet area to outlet area lies between and including the range of 2:1 to 20:1. Funnel angles are specified according to whether the funneled rotary foil is functioning as a wind-driving device or as a wind-driven device.
The funneled rotary foil is a highly efficient propeller-like device capable of producing a lift to drag (L/D) ratio of 100 to 1. However, a conventional propeller is also useful in the present invention and the term impeller herein includes either a conventional propeller or a funneled rotary foil (FRF).
The laws of aerodynamics applying to aircraft wings also apply to rotary airfoils. The conventional formulas utilize the terminology appropriate to the aerodynamic forces on an aircraft wing, as follows:
Lift=Cxcfx81/2V2S and
Drag=CDxcfx81/2V2S where CL is the coefficient of lift, CD is the coefficient of drag, xcfx81 is air density, V is the air velocity, and S is the wing area. A line from the leading edge to the trailing edge of the airfoil is the chord of the airfoil, and an angle xcex1 between the chord and the direction of airflow relative to the airfoil is termed the angle of attack. CL depends mainly on the angle of attack. CL values range from negative to about 4.5, but are usually from 0.3 to 1.5. Conventional wings stall (lose lift) above an xcex1 of about 15xc2x0. CD usually ranges from 0.004 to 20, and is composed of frictional drag due to air passing over the surface of the airfoil plus other drag forces produced by separation of airflow at the top of a wing at high angles of attack and air circulating lengthwise over the wing.
It is evident that lift and drag differ only in the coefficients CL and CD in the above formulas. The coefficient of drag, CD at medium speeds (below 0.8 of the speed of sound) is due mainly to frictional drag, which increases as velocity squared.
The coefficient of lift, CL, increases linearly; therefore, the lower the angle of attack xcex1 the larger will be the L/D. The highest efficiency of a rotary airfoil when the airfoil is rotated by an energy source depends on attaining the highest lift to drag ratio possible.
While a funneled rotary foil or a propeller is useful as an impeller to produce thrust, it would be desirable to provide an improved fluid motor, which amplifies this thrust for the propulsion of trucks, planes, tanks, rockets, boats, and machinery. It would also be desirable to provide an improved fluid motor, which amplifies this thrust for powering rotating machinery such as electric generators, pumps, compressors, and similar equipment.
Briefly stated, the invention comprises a fluid motor having a primary fluid motor constructed to be rotated by secondary fluid motors so as to amplify and reorient the thrust created by the secondary fluid motors to achieve a high coefficient of performance. The fluid motors preferably have impellers constructed as funneled rotary foils, but the impellers could also be conventional propellers or contracted as a rotary funneled disc as explained later.
The invention may be summarized as a fluid motor comprising a primary fluid motor having at least one primary rotating fluid impeller arranged to generate thrust along a primary axis, a plurality of secondary fluid motors each having at least one secondary rotating fluid impeller arranged to generate thrust along a secondary axis, and secondary drive means adapted to cause the secondary fluid impellers to rotate, the secondary fluid motors being disposed on the primary fluid motor with their respective secondary axes directed with respect to the primary axis to cause the primary fluid impeller to rotate about the primary axis, whereby thrust along the primary axis is generated by the secondary drive means.
In the preferred form of the invention the primary and secondary impellers are constructed as funneled rotary foils in accordance with the aforementioned Ser. No. 09/682,455, and the primary fluid motor includes a plurality of primary fluid impellers.